Baylor Ecotoxicologist Identifies Drugs In Texas Waters, Organisms

Dr. Bryan Brooks, assistant professor of environmental studies in the Center for Reservoir and Aquatic Systems Research

Pharmaceutical contaminants found in fish and invertebrates caught downstream from urban areas in Texas may cause neurological, biochemical and physiological changes in the animals, according to Baylor University researchers.

Dr. Bryan Brooks, assistant professor of environmental studies at Baylor's Center for Reservoir and Aquatic Systems Research, and his team have documented fluoxetine, an ingredient in antidepressants such as Prozac, in organisms that reside downstream from municipal water treatment facilities.

Although treated Texas waters may meet current federal standards, Brooks said no federal water quality standards exist for pharmaceuticals because the substances are not considered toxic at low levels. But their effects in surface waters are not well understood.

Brooks previously reported finding the substances in fish, but further research has confirmed fluoxetines in aquatic invertebrates.

Brooks focused on effluent-dominated streams and rivers in Texas, where he and his researchers performed forensic tests on fish and invertebrates.

In Waco, more than 15 million gallons of treated water a day are pumped into the Brazos River, which empties into the Gulf of Mexico, he said.

"When male fish are exposed to critical levels of estrogenic substances, which enter the water from sources such as birth control pills, the fish can be feminized, and their secondary sexual characteristics become suppressed. We're also observing antidepressants in fish tissue at levels that may influence [fish] behavior," Brooks said, adding that more study is needed to determine whether antidepressant build-up in the fish may impact aggression, mating and other behaviors necessary for fish survival.

In lab studies, Brooks has observed male fish exposed to estrogens to develop female physical characteristics and lose the ability to reproduce.

Brooks expressed that the substances should not affect humans who eat the fish. "If these substances accumulate in fish tissue, humans may ingest these products from fish. We doubt

that they'll be affected, because the amount of exposure is well below therapeutic levels," Brooks said.

Brooks presented his findings in August at a symposium on the environmental aspects of pharmaceuticals and personal care products during the 228th national meeting of the American Chemical Society in Philadelphia.